1. Field of the Invention
The present invention relates to an improvement in a fuel supply system for an engine, in which a discharge port in a pump chamber in a fuel pump driven by the engine to draw up fuel in a fuel tank is connected to an inlet port which is provided in a fuel reservoir having an air vent and which is controlled in opening and closing by a float valve so that the fuel in the fuel reservoir is supplied to the engine.
2. Description of the Related Art
There is a conventional fuel supply system for an engine, in which a normally-closed one-way valve is incorporated in a fuel passage extending between a fuel tank and a fuel pump for drawing up fuel in the tank for permitting a flow of fuel only in one direction from the fuel tank to the fuel pump so that the fuel in a pump chamber in the fuel pump is prevented by the one-way valve from flowing back to the fuel tank during stoppage of the operation of the engine, thereby enhancing the hot startability of the engine (see Japanese Patent Application Laid-open No. 11-82207).
In the conventional system, however, when the engine itself and the its atmosphere are at a high temperature during stoppage of the operation of the engine, fuel vapor is generated in the pump chamber in the fuel pump and impedes the pumping function of the fuel pump at the hot start of the engine in some cases, resulting in a detracted startability.